植物生理

Directed movement in response to chemical attractants is of crucial importance to Agrobacterium tumefaciens. Motility is a determinant of rhizosphere competence (1), and chemotaxis a conditional requirement for virulence (2,3). A. tumefaciens is attracted toward a variety of sug ...

Expression of the virulence genes of Agrobacterium tumefaciens occurs in acidic media containing sugars and certain phenolics secreted at plant wounds. In some strains of A. tumefaciens, exposure to these inducing conditions leads to inhibition of bacterial growth, which can then be fo ...

Living organisms have been continuously evolving by assimilating new genetic material from the environment. However, this progress is very slow and often limited to transfer of genetic materials among closely related species. Recent developments in molecular biology and gene tra ...

Reliable and efficient methods of transferring cloned genes into plants are essential for engineering crops with desired traits. The Gram-negative soil bacteria, Agrobacterium tumefaciens and A. rhizogenes, are natural genetic engineers, capable of transforming a range of dico ...

Although a number of protocols are available for the regeneration of oilseed rape protoplasts (1–4), there are almost no reports of successful Agrobacterium tumefaciens-mediated transformation of protoplasts resulting in transgenic plants. Plant regeneration from protop ...

The commercial importance of oilseed rape (Brassica nupus L.) makes it desirable to have an efficient transformation protocol for practical applications. With the exception of a few reports, transformation experiments with B. napus using Agrobacterium tumefaciens yielding tra ...

Since the first reports of tobacco transformation experiments in 1983, a number of fundamental processes, such as gene expression, cell metabolism, or plant development, are being studied using gene transfer experiments. The spectrum of plant species amenable to transformation is co ...

The hordeivirus group of RNA viruses contains three members: barley stripe mosaic virus (BSMV), poa semilatent virus (PSLV), and lychnis ringspot virus (LRSV), with anthoxanthum latent bleaching virus (ALBV) considered to be a possible fourth member (1). Hordeiviruses have a diverse host ...

The Rhabdoviridae family consists of a large number of nonsegmented negative-strand RNA viruses. As a group, the rhabdoviruses cause many serious plant and animal diseases that have detrimental effects on agricultural productivity, public health, and wildlife populations. The me ...

Plant reoviruses are classified in three genera in the family Reoviridae: Phytoreovirus, Fijivirus, and Oryzavirus. Fifteen viruses, including possible members, are described (1). With two exceptions, all of them infect plants in gramineae. They possess 10–12 segmented double-str ...

Much has been written on the possible risks arising from the use of virus-resistant transgenic crop plants but little of the benefits that might result. Many of the potential benefits are self-evident and relate to improved disease control, but others are less so and arise from such indirect effec ...

Recent advances in the understanding of the molecular mechanisms of how viruses function and how they interact with plants have led to the development of various nonconventional approaches to protection of plants against viruses. Many of these approaches involve the introduction of v ...

Viral diseases cause significant losses to almost all crops throughout the world. Infections with plant viruses can either cause direct yield losses or lead to unacceptable levels of postharvest damage to the crops. Besides measures to limit the virus incidence, the ultimate way to minimi ...

Members of the caulimovirus group (1) each have a circular double-stranded DNA genome of approx 8 kbp that is encapsidated in a spherical, naked nucleocapsid of approx 50 nm diameter (Fig. 1). Caulimoviruses characteristically produce subcellular inclusion bodies in infected tissues t ...

The expression of viral coat protein (CP) genes in transgenic plants can lead to different phenotypes of resistance (1). Occasionally, transgenic plants escape infection completely and do not accumulate virus or develop symptoms. In other cases, local and systemic virus accumulation a ...

This chapter describes methods to assess agronomic performance among plants of existing plant cultivars that have been transformed with viral genes for the purpose of achieving resistance to the virus (1). The principles and general guidelines for selection among plants altered by tra ...

This chapter describes methods to detect and assess commercial resistance to virus disease that may be conferred on existing plant cultivars by their transformation with genes derived from viruses (1). The principles and general guidelines for selection among plants altered by trans ...

A number of methods have been used for the quantitation of virus within infected plants. Early ones used physical techniques such as dry-wt and particle counts; more recently, serological and nucleic acid-based methods have been developed. These methods are all based on a physical aspect of the v ...

The polymerase chain reaction (PCR) is a technique that enables the specific amplification and hence detection of target DNA sequences from complex mixtures of nucleic acid. A combination of short, specific primers and thermostable DNA polymerases are used to amplify the target sequen ...

Unlike for fungal and bacterial diseases, no direct method for the control of viral diseases is yet available. The early detection of plant viruses constitutes, therefore, one of the main ways of controlling these diseases, and so sensitive detection systems are essential. Until now, methods ...